PROJECT SUMMARY/ABSTRACT Globally, 20 million of the world?s 37 million people living with HIV are on antiretroviral therapy (ART) representing immense and encouraging success with access to HIV care. ART prevents disease, death and HIV transmission and HIV-positive persons can expect to live as long as their HIV-negative peers. However, the burden of supplying ART is enormous. In South Africa alone, 7.1 million HIV-positive persons will require ART for life and only 3.9 million are currently on ART. Prescription refills consume 70% of current pharmacy load, contributing to the overcrowding of clinics. Further, over four years, a third of HIV-positive persons are lost from care due to barriers of collecting ART at clinic pharmacies including long waits and inconvenient hours. To address this resupply gap, efforts are underway to support medication refills outside the clinic, including private pharmacy pick-up, but in rural communities without pharmacies and a formal address system, this has been challenging. How ART delivery will be scaled up and distributed for life to millions of people is a critical question for sustainable HIV treatment. Decentralized ART delivery, i.e. ART resupply outside the clinic, can increase the number of persons receiving safe ART resupply and monitoring. Specifically, community-based mobile vans are increasingly being tested as a venue for ART resupply and monitoring. Tools are needed to determine where mobile vans should be stationed, the optimal delivery time, and the number clients served. Amazon.com is the largest internet-based retailer in the world with experience delivering goods on time to persons in diverse settings, including rural areas. We will collaborate with Amazon?s routing science scientists and adapt their algorithms to optimize delivery to efficiently meet ART demand. Further, for participants who are willing to pay a delivery fee, home ART delivery can simplify their resupply (the Amazon Prime model). A fee for home delivery of ART could increase engagement in care and offset costs of home delivery. Data driven ART delivery algorithms have the potential to sustain 90% viral suppression among persons on ART. Working closely with Amazon, we propose to develop and test a software application (Deliver Health) that uses spatial GPS data on where HIV-positive clients live, distance from mobile van potential locations, street maps, and client needs and preferences to inform an objective algorithm. The Deliver Health algorithm uses these data to maximizes the number of clients served by the mobile van location at a specific time. We will compare algorithm and study coordinator determined mobile van placement for ART delivery in a cluster randomized study (N=600). Separately, we will test a fee for home delivery service in a randomized pilot study (N=120) compared to mobile van ART resupply and monitoring. The study outcomes are the proportion of HIV- positive persons virally suppressed and the number of missed ART refills. We will also assess costs and conduct participatory research to support implementation of decentralized strategies for ART resupply.